Low-temperature sintering of 0.85CaWO4–0.15LaNbO4 ceramics

Microwave dielectric properties of 0.85CaWO4–0.15LaNbO4 (CWLN) ceramics were investigated as a function of H3BO3, Li2CO3 content and sintering temperature. With the co-addition of 3.0 wt.% H3BO3–1.0 wt.% Li2CO3, the sintering temperature could be effectively reduced from 1150 °C for pure CWLN ceramics to 900 °C without any degradation of dielectric properties. These results are due to the enhancement of the sinterability of CWLN by liquid phase sintering. For the specimens with H3BO3–Li2CO3 sintered at 900 °C for 3 h, the dielectric constant (K) did not changed remarkably. However, the quality factor (Qf) and the temperature coefficient of resonant frequency (TCF) increased up to y = 1.0 of 3.0 wt.% H3BO3–y wt.% Li2CO3, and then decreased due to the formation of the secondary phases. Typically, K of 11.8, Qf of 45,200 GHz and TCF of −23.1 ppm/°C were obtained for the specimens of CWLN with 3.0 wt.% H3BO3–1.0 wt.% Li2CO3 sintered at 900 °C for 3 h.